Excerpt:
A grower creating a bespoke protein product has no direct control over the way his cows, or any other animal, become meat. The industry is built on the presence of a middleman, the processing companies. A rancher ships cows to the front of the slaughterhouse, and then meat comes out the back. What happens in between is an open question, and Pettit suspects that mixed product is far more common than consumers realize: An order for 10,000 pounds of certified Angus beef might be 7,000 pounds of Angus and 3,000 pounds of whatever ...
In a famous test, a journalist delivering fast food hamburger patties to a lab for DNA testing found that a single burger could have meat mixed from a hundred or more different cows. Those cows can come from different herds, different sources, even different states and countries, all tossed into the same grinder.